Nov charlie you might be surprised if you do the numbers that it is much less of a detour than you think particularly if you are coasting out at sfd. Given the extra time getting into paris (and cost) i bet it will be almost as quick and cheaper. Also where else would you stop for customs with l2k and better still lille being easy cheap options.
Toussus is easy and the airspace actually isnt daunting but looks it. Plan logically and it will fall into place or let us know if not. I have not done it but i gather its not great for getting into paris but others will know better whats involved.